(a) Field of the Invention
The present invention relates to a spray paint gun head, and more particularly, to one allows easy corresponding assembly of an abutting structure that gives pressure stabilizing effect without matching error of an axial hole of insertion configuration.
(b) Description of the Prior Art
To secure consistent, evenly distributed air output, an air outlet end of a spray paint gun of the prior art is provided with a structure of pressure regulation. As illustrated in FIGS. 3 and 4 of the accompanying drawings, a spray paint gun (A) delivering air at a consistent pressure comprises a pressure regulation ring (B), a nozzle (C), a spray head (D) and a nut (E). The pressure regulation ring (B) provided at the tip of a spray gun (A) is engaged to a nozzle (C) through the pressure regulation ring (B), and the nut (E) coupled to the spray head (D) that secures the nozzle (C) to the tip of the spray gun (A). Wherein, the tip of the spray gun (A) related to a circular wall having male threads (A1) on its external surface and a circular recess (A2) therein. A screw hole (A3) is formed in the recess (A2) having a regulation shaft (F) extended from the center of a passage formed within the screw hole (A3). An air outlet (A4) is provided on the outer ring of the screw hole (A3) and another air outlet (A5) is provided on the circular wall in relation to the recess (A2). A pressure regulation ring (B) is provided that it can be inserted into the recess (A2), and a circular groove (B1) in a width properly corresponding to the diameter of the air outlet (A4) is formed on its side facing the recess (A2). Multiple through holes (B2) are provided in the circular groove (B1). Furthermore, a hollow screwed tube (C1) is formed at the rear end of the nozzle (C) to be inserted through the pressure regulation ring (B) and engaged by the screw hole (A3). Meanwhile, the body of the nozzle (C) extends into the recess (A2) to hold its rear tightly against the pressure regulation ring (B). A circular groove (C2) is formed in the nozzle (C) on its rear side facing the pressure regulation ring (B). Multiple air outlets (C3) are provided in the circular groove (C2) and penetrating through the nozzle (C) until reaching a circular channel (C5) provided around a nozzle tip (C4) at the front side of the nozzle (C). A push-pull surface (C51) is formed on the outer surface of the circular channel (5). As for the spray head (D), it is inserted to the nut (E), which in turn is engaged to the male threads (A1) provided at the tip of the spray gun (A). The spray head (D) then holds against the front of the nozzle (C) and is provided inside a circular indention (D1) with a push-pull wall (D2). The push-pull wall (D2) is abutted to the push-pull surface (C51) of the circular channel (C5) in front of the nozzle (C). Air ducts (D3) provided on the outer ring of the push-pull wall (D2) are connected two air outlet bases (D4) outside the spray head (D). A spray hole (D5) to allow insertion of the nozzle tip (C4) is provided in the center of the circular indention (D1).
During the application of the spray paint gun of the prior art, high pressure air flowing in the spray gun (A) is delivered from the air outlet (A4) in the recess (A2) on the front end of the spray gun and another air outlet (A5) on the surface of the outer ring of the screw hole (A1), then conducted into the air passage in the nozzle (C) and the spray head (D). The pressurized air leaving the air out (A4) in the recess (A2) is immediately sent into the circular groove (B1) of the pressure regulation ring (B) to become stabilized inside a port formed by the circular groove (B1) before flowing into the circular groove (C2) in the nozzle (C) to be further buffered. The buffered air in the circular groove (C2) flows to the circular channel (C5) on the front side through the air outlet (C3) to enter into the spray head (D) to be conducted into the circular indention (D1) by a closed passage formed by the push-pull surface (C51) on the circular channel (C5) abutted by the push-pull wall (D2). Furthermore, the air delivered from the surface on the external ring of the circular recess (A2) flows in a space formed on the surface of the outer ring to the push-pull wall (D2). Finally, the air in the circular indention (D1) is jetted through a gap between a spray hole (D5) and the nozzle tip (C4) to atomize the mix of coating and air flow jetted from the nozzle (C) by disturbance jointly produced with the air delivered from the air bases (D4) externally provided to the air ducts (D3).
However, in the prior art, the spray body is essentially molded in one piece of aluminum alloy with a stainless steel surface after plating and thermal treatment. The plated surface is given with a certain film thickness. As the circular recess (A2) in the front end of the spray gun relates to an open recess, it is plated at the same time with the spray body, making it difficult for precision control of its diameter. A temperature factor of thermal treatment also presents another potential variance to deformation of the circular wall of the recess (A2) to further affect the true roundness of the recess (A2). Therefore, upon inserting the regulation ring (B) into the recess (A2), abnormal resistance is encountered. The pressure regulation ring (B) is made of plastic material and is vulnerable to be deformed, if not damaged when forced in by hammering or other means, affecting the transfer of the air in the circular groove (B1) and those through holes (B2).
The primary purpose of the present invention is to provide an improved structure of a spray paint gun head with by eliminating matching error of an axial hole to help all the related elements giving their optimal performance. To achieve the purpose, the abutting structure inside the spray head of the prior art is waived, instead, an improvement made to pressure regulation structure at where the front end of the spray gun is abutted to the nozzle, essentially characterized by that:
A screw hole, formed in the front section of a passage of a spray gun wherein a pressure regulation shaft extends, connects to a nozzle. The surface of the tip of the spray gun is formed an inner and an outer circular recesses, and each recess is respectively provided with an air outlet. A gasket is inserted between the spray gun and the nozzle. Slots arranged in circular keeping a proper distance among one another are respectively provided on the gasket to match said inner and outer recesses. A hollow screwed tube is formed in the rear of the nozzle to receive the gasket before being engaged to a screw hole at the tip of the spray gun. Another inner circular and outer recesses are also formed on the rear side of the screw tube, wherein, air ventilation and air outlet are respectively provided penetrating all way to reach the front side of the nozzle. With the inner and the outer recesses of the nozzle being abutted to the slots of the gasket to fully attach to the matching inner and outer recesses on the surface of the front of the spray gun, a pressure regulation port is formed. Meanwhile, multiple male threads on the outer side of the spray body are engaged to a nut to merely for the spray head to be secured in position by holding against the nozzle.